Japanese Patent Application No. 2002-95057 filed on Mar. 29, 2002, is hereby incorporated by reference in its entirety.
The present invention relates to a method of forming a ferroelectric film, a ferroelectric memory, a method of manufacturing the ferroelectric memory, a semiconductor device, and a method of manufacturing the semiconductor device.
A ferroelectric memory (FeRAM) retains data by spontaneous polarization of a ferroelectric film used in a capacitor section. In recent years, a semiconductor device utilizing the ferroelectric memory has attracted attention.
Conventionally, a ferroelectric film having good characteristics is formed by crystallizing a ferroelectric material by a heat treatment at a high temperature. For example, a heat treatment at a temperature as high as 600 to 700xc2x0 C. is necessary for crystallizing Pb(Zr,Ti)O3 (PZT), and a heat treatment at a temperature as high as 700 to 800xc2x0 C. is necessary for crystallizing SrBi2Ta2O9 (SBT). The ferroelectric material is crystallized by using a heat treatment furnace, for example.
However, the heat treatment at a high temperature causes elements to be significantly damaged. For example, characteristics of a peripheral section such as an electrode deteriorate due to atom diffusion. In the case where semiconductor devices such as transistors are integrated in a ferroelectric memory, characteristics of the transistors and the like deteriorate due to thermal load applied by the high-temperature heat treatment.
The present invention may provide a method of forming a ferroelectric film capable of reducing thermal load applied during crystallization of a ferroelectric. The present invention may also provide a method of manufacturing a ferroelectric memory by using the method of forming a ferroelectric film of the present invention, and a ferroelectric memory manufactured by using this method. The present invention may further provide a method of manufacturing a semiconductor device by using the method of manufacturing a ferroelectric memory of the present invention, and a semiconductor device manufactured by using this method.
A method of forming a ferroelectric film according to one aspect of the present invention comprises applying pulsed laser light or pulsed lamp light to an amorphous oxide film formed over a substrate to form microcrystalline nuclei of oxide in the film, and
applying pulsed laser light or pulsed lamp light to the film to crystallize the oxide, so that a ferroelectric film is formed.